The invention relates to a coke oven of horizontal construction (non-recovery/heat recovery type), in which at least part of the interior walls of a coking chamber is configured as secondary heating surfaces by coating them with a high-emission coating (HEB), with the emission degree of this high-emission coating being equal to or greater than 0.9. This HEB preferably consists of the substances Cr2O3 or Fe2O3 or of a mixture containing any one of these substances, with the portion of Fe2O3 amounting to at least 25% by wt. in a mixture and with the portion of Cr2O3 amounting to at least 20% by wt. in a mixture.
Coke ovens of horizontal construction are known from prior art in technology and they are in frequent use. Examples of such coke ovens are described in U.S. Pat. No. 4,111,757, U.S. Pat. No. 4,344,820, U.S. Pat. No. 6,596,128 B2 or DE 691 06 312 T2. A survey of coke ovens and common design types is given by W. E. Buss et al. in Iron and Steel Engineer, 33-38, January 1999.
They are distinguished in that the supply of the required energy is partly taken directly from the combustion of light-volatile coal constituents in the oven free space above the coal cake or from the coal charge. Another part of the coking energy is carried in through walls heated by flue gases on their rear side and through the chamber floor into the coal cake or coal charge.
On account of a direct energy impact, the growth in thickness of the upper layer of the carbonised coke is the fastest. Carbonised layers which grow in parallel to the walls or from the bottom and in parallel to the chamber floor, therefore, at the end of the coking time, are less in thickness than the upper layer.
Known from prior art in technology are different approaches designed to speed up the coking time of coal. An increase in temperature in the coking chamber which would cause an acceleration of the coking process leads to a higher loss of coal chemicals and as a rule it is impossible for reasons related to material. Therefore, preference was given to try to improve the indirect heat transport through the walls and chamber floor, for example in the way described in DE 10 2006 026521.
For the constructively different horizontal chamber ovens, the European patent EP 0 742 276 B1 describes a method to improve heat transfer from parallel heating flues outside the actual oven space into the coal charge. According to this method, the surfaces of heating flues extending in parallel to the coke oven chamber are coated so that they act as a black body, thus improving heat transport through the wall.
Still there is a demand, however, to reduce the coking time and thereby to improve the economic efficiency of this method.